Monthly Archives: September 2017

Hi guys,
Sorry for the delay: a huge change has happened in my life recently — I moved from Moscow, Russia to Limassol, Cyprus, where I now live and work.
I am still polishing the next part of the “Command-line Infrastructure” series, and today I am here to present you another significant update to the DNS Zones Synchronization script:

Name query modes introduced. Right now, here are two modes:

“1” – The script will try to retrieve authoritative nameservers for a zone and then will you them to resolve records in that zone.

“0” – The script will use nameservers specified in the config file.

Specify the required mode for each zone in the new column conveniently named “Mode”. Also, instead of specifying “0”, you can leave the column empty.

This has led to another new feature: From now on, the script supports not only IP addresses as NS servers, but DNS names too. Therefore, “ExtIP” and “IntIP” columns in the configuration file have been renamed to “ExtNS” and “IntNS”.

Even more: you can now leave external nameserver field (ExtNS) empty. In that case, the script will use default operating system DNS servers.

Here is a table for you to better understand how these new features work together:

Mode

ExtNS Type

Result

0

IP Address

Names in the zone resolved using ExtNS IP address.

1

IP Address

ExtNS IP address used to find authoritative NSes for the zone.
The first authoritative NS then used to resolve names in the zone.

0

DNS Name

Default OS DNS servers used to resolve ExtNS DNS name to an IP address.
This IP address then used to resolve names in the zone.

1

DNS Name

Default OS DNS servers used to resolve ExtNS DNS name to an IP address.
This IP address then used to find authoritative NSes for the zone.
The first authoritative NS then used to resolve names in the zone.

0

Empty

Names in the zone resolved using default OS DNS servers.

1

Empty

Default OS DNS servers used to find authoritative NSes for the zone.
The first authoritative NS then used to resolve names in the zone.

Note, that a query mode does not affect the internal name server at all. Here’s a table for the “IntNS” column as well:

IntNS Type

Result

IP Address

Requests are sent to this IP address.

DNS Name

Default OS DNS servers used to resolve IntNS DNS name to an IP address.
Then requests are sent to this IP address.